function showPic(whichpic){
   if(!document.getElementById("placeholder")) return false;
   var placeholder=document.getElementById("placeholder");
   var source=whichpic.getAttribute("href");
   placeholder.setAttribute("src",source);
   if(!document.getElementById("description")) return false;
   if(whichpic.getAttribute("title")){
   	 var text=whichpic.getAttribute("title");
   }else{
   	var text="";
   }
   var description=document.getElementById("description");
   if(description.firstChild.nodeType==3){
   	 description.firstChild.nodeValue=text;
   }
   return false;
}

function preparePlaceholder(){
   if(!document.createElement) return false;
   if(!document.createTextNode) return false;
   if(!document.getElementById("imagegallery")) return false;
   var placeholder=document.createElement("img");
   placeholder.setAttribute("id","placeholder");
   placeholder.setAttribute("src","images/placeholder.gif");
   placeholder.setAttribute("alt","my image gallery");
   var description=document.createElement("p");
   description.setAttribute("id","description");
   var desctext=document.createTextNode("Choose an image");
   description.appendChild(desctext);
   var gallery=document.getElementById("imagegallery");
   insertAfter(description,gallery);
   insertAfter(placeholder,description);
}

function prepareGallery(){
   if(!document.getElementById) return false;
   if(!document.getElementsByTagName) return false;
   if(!document.getElementById("imagegallery")) return false;
   var gallery=document.getElementById("imagegallery");
   var links=gallery.getElementsByTagName("a");
   for(var i=0;i<links.length;i++){
   	    links[i].onclick=function(){
   	    	return showPic(this);
   	    }
   }
}

